Personality genetics, 2002

The study of the genetics of personality looks for effects of genetic differences on psychological differences between people. The most replicated associations have been between the dopamine D4 receptor gene and "novelty seeking" and between the serotonin reuptake transporter gene and anxiety. But even these reports are controversial, and their effects are too small to add to existing scientific theories or allow for clinical use in psychological counseling. Simultaneously studying three polymorphisms suggests that gene-gene interactions are partly responsible for these difficulties. Recently a linkage of anxiety-related traits to chromosome 8p21-23 has been replicated, and we may be close to isolating relevant genes in the region. But uncertainty about psychological phenotypes remains, and it is not clear whether future breakthroughs will require studies of thousands of genes in very large samples, or revolutions in the current assumptions and methods of personality genetics.